I used one of the earlier Singlepoint sights many years ago on an old Mercury. Fantastic for close range farmyard use, it accounted for a great many rats, although the dot was far too large for even contemplating rabbits at, say, 30 yards.

About six years ago I bought a Hawke red dot. Can't remember the exact model...it was right at the budget end of the price range, the Sport Dot, or something? Had it on a Crosman Model 1. It seemed okay, but I never got it used for my intended ratting purposes, but felt it would be fine. I did feel, however, that adjustment was pretty coarse, so slight lack of ability for "fine tuning".

About a year ago I got a Walther Competiton Red Dot. This seems lovely. It's on my 2240 mini-carbine. Again, it hasn't actually made it to the farmyard as yet, but this seems really good. Nice small dot on low power settings and very compact.

Must have a play with it soon, it's been in the cupboard for yonks, unused!!!

I also feel that, for many scenarios, the dot sight is a formidable and useful system.